Turns out, in the chaotic singles’ scene of crowded African penguin colonies, the secret to finding your true love is not just a feather in your cap but the plumage on your chest!
If you have ever seen a colony of African penguins, you might have wondered how they can recognize their mates and friends among the hundreds of similar-looking birds. Well, it turns out that these penguins have a secret code: their polka dot patterns.
African penguins, also known as jackass penguins because of their donkey-like braying, are native to the coasts of Namibia and South Africa. They are about 60 to 70 cm tall and weigh about 2 to 5 kg. They have black backs and white bellies, with a black band across the chest and a black spot on each side of the neck. But what makes them unique is the array of black dots that adorn their white fronts. These dots vary in number, size, shape and position for each individual penguin, making them like fingerprints or facial features for humans.
A team of researchers from Italy and Finland wanted to test whether these dots play a role in individual recognition for African penguins. They conducted a simple experiment with 12 penguins from a colony at Zoomarine Italia, a marine park near Rome, publishing their findings in the journal Animal Behaviour.
The researchers built a small enclosure with plywood walls that prevented the penguins from seeing over them. They placed cameras on either end of the enclosure and life-size pictures of two penguins on one of the far walls. One picture was of the test penguin’s mate, while the other was of a different familiar penguin from the same colony. The researchers then let one penguin enter the enclosure and observed its behavior.
They found that the test penguins spent more time looking at the picture of their mate than at the picture of the other penguin, even when the heads on the pictures were blurred. This suggested that the penguins could tell their partners apart by their chest patterns alone.
To confirm this, the researchers repeated the experiment with two pictures of the test penguin’s mate, one with the dots intact and one with the dots removed. The test penguins preferred the picture with the dots, indicating that they used these spots as visual cues for recognition. However, when the test penguins were shown two pictures without dots, one of their mate and one of another penguin, they did not show any preference, suggesting that they could not recognize their partners without the dots.
The researchers concluded that African penguins use their polka dot patterns as a way to identify each other in their large and noisy colonies. This is one of the first studies to show that birds can use visual cues for individual recognition, as most birds rely on auditory cues such as calls or songs. The researchers speculated that African penguins may have evolved this ability to cope with their harsh and windy environment, where vocal communication may be difficult or unreliable.
Mark Hauber, a comparative psychologist at the City University of New York, who was not part of the research, told Science that researchers have traditionally viewed the capacity to recognize individuals through visual cues as something “very special and cognitively difficult.” The study’s results suggest, therefore, that African penguins possess greater intelligence than previously thought.
